LONDON—Diageo PLC said Chief Operating Officer Ivan Menezes will become chief executive, ending more than a decade of leadership by Paul Walsh.

The 53-year-old Mr. Menezes, who was widely expected to ascend to the top job, will move into his new role on July 1. He will be charged with reinvigorating sales growth as important spirits markets slow and with using the London-based company's healthy cash position to expand.